The existence of post-transition state bifurcations (PTSBs) on potential energy surfaces for organic and biological reaction mechanisms has been known for decades, but only recently have theoretical chemists come to terms with the implications of this unusual feature of some potential energy surfaces. Beyond simply discovering bifurcations, computational chemists are developing techniques to understand what aspects of molecular structure and vibrations control the product selectivity in systems containing bifurcations. We have found a variety of reactions involving PTSBs and continue to look for more, all the while seeking deeper understanding of their origins and implications. Key papers:

Hare, S. R.; Tantillo, D. J.Pure Appl. Chem.2017, 89, 679-698: "Post-Transition State Bifurcations Gain Momentum – Current State of the Field," invited as part of a special issue associated with the ICPOC23 meeting.